Fatigue characterization study of CFRP under hygrothermal environment based on continuum damage mechanics model
Jianfeng Li, Mingqing Xiao, Junliang Ding, Haizhen Zhu, Yaojun Chen
Abstract
Abstract Carbon fibre‐reinforced polymers (CFRPs) are now widely used for high‐performance fields such as aircraft structures. On average, these structural components are subjected with more than 10 8 cycles during their lifetime. To make full use of the mechanical performance of CFRP, the fatigue behaviour needs to be well studied. Nevertheless, at present, fatigue behaviour and failure mechanisms of CFRP under hygrothermal environment are not sufficiently investigated. To obtain comprehensive knowledge about fatigue behaviour and failure mechanisms of CFRP, hygrothermal tests and ultrasonic three‐point bending fatigue experiments are designed. Besides, a damage variable is proposed as the function of stiffness to evaluate the fatigue degradation of the composite. A nonlinear continuum damage mechanics (CDM) model is compared with three models and employed for fatigue damage evolution under cyclic loading. Compared with the other three models, the experimental results show a better consistency between the result of the CDM model and the measured damage. Meanwhile, the damage variable expresses the damage state of the composite effectively. The damage variable and the CDM model provide a reference for fatigue characterization analysis and further life prediction of CFRP.